The recent discovery by Alec Jeffreys of minisatellite DNA sequences that are highly polymorphic has made it possible to genetically "fingerprint" individuals by Southern hybridization of their DNA. Even very closely related people will show some differences in the size of the approximately 50 distinctive bands seen in a typical pattern. By definition, each of these bands is in close genetic linkage to some portion of the chromosome and therefore to genes that might be involved in disease. Our plan in this project is to "fingerprint" a large number of BLSA participants using this technique, and to try to identify specific bands that may be linked to specific patterns of age-related physiologic changes and/or age-related disease.